When you get tissues from a human to study the genes would you get it from a healthy person or a ill person ?

Question: When you get tissues from a human to study the genes would you get it from a healthy person or a ill person ?

Asked by shooshii to Michaela on 16 Jun 2010 in Categories: Your Research.
- Michaela Livingstone answered on 16 Jun 2010:
  
  A tissue sample involves only taking a small collection of cells from the body and in most cases can be done fairly harmlessly with very little pain, etc – so this can be done from consenting adults whether they are ill or not. It depends really what you’re researching, for example if you wanted to study what genes are switched on when a disease develops, you’d really want to compare the disease tissue to the healthy tissue.
  
  In the case of cells that I use, they come from tumour samples that are then adapted to grow in a petri dish so that we can keep them for a long time to study. This is just because tumour cells can divide a lot more than normal cells so are easier to work with in this sense.

Question: When you get tissues from a human to study the genes would you get it from a healthy person or a ill person ?